A variety of electronic cards are utilized to transport information. For example, smartcards 100 (FIG. 1) are used with cellular telephones to provide subscriber identification information to a cellular telephone. Smartcards include a microprocessor 102 and an electronically erasable programmable read only memory (EEPROM) 104. The microprocessor communicates with a port 106 through a communication bus 108 and memory 104 via data bus 110. The EEPROM stores information, such as an account identification, communicated to the cellular telephone when the smartcard is inserted into the cellular telephone. Another smartcard device 200 is illustrated in FIG. 2. This smartcard includes a first microprocessor 202 coupled to an EEPROM 204 and a port 206. Microprocessor 202 is connected to port 206 vi a bus 208 and to EEPROM 204 via data bus 210. A second microprocessor 212 is coupled to an EEPROM 214 and a port 216. The microprocessor 212 and EEPROM 214 are connected by a data bus 220. Microprocessor 212 is connected to port 216 via bus 218. EEPROMs 204 and 214 store respective information for different accounts. Thus, one EEPROM can be associated with a holder's personal account and the other EEPROM can be associated with the holder's business account.
A memory card 300 (FIG. 3) includes a port 302 and a memory 304 coupled by a data bus 306. The memory stores an account balance which is credited or debited when the memory card 300 is coupled to a memory card compatible device. For example, the memory card is used for pay phone, banking, cinema, and mass transit applications.
Because smartcards 100, 200 and memory cards 300 employ different communication signal formats, and store different information, these cards can not be used interchangeably. For example, memory card 300 employees synchronous communication whereas smartcards 100 and 200 utilize asynchronous communication.
Accordingly, there is a need for devices and information cards which are more versatile.